Method of, and apparatus for, recording address information to disc medium

ABSTRACT

In step S 1 , the address generator generates address information composed of a sync signal which is recorded on an optical disc, address data and an error correction code for the address data, pre-encodes and supplies it to a modulator. At the same time, a carrier signal generator generates a carrier signal which is to carry the address information, and supplies it to the modulator. In step S 2 , the modulator makes MSK modulation of the carrier signal supplied from the carrier signal generator on the basis of the pre-encoded address information supplied from the address generator, and supplies a resultant MSK modulation signal to a wobbling unit. In step S 3 , the wobbling unit forms, on the optical disc, a spiral groove wobbled adaptively to the MSK modulation signal supplied from the modulator. In this optical disc, a given address can be accessed quickly and accurately.

CROSS-REFERENCE TO RELATED APPLICATIONS

The present application is a continuation of U.S. application Ser. No.10/276,383 filed on Nov. 15, 2002, and in turn claims priority to JP2001-078239 filed on Mar. 19, 2001, JP 2001-170610 filed on Jun. 6,2001, and PCT/JP02/02615 filed on Mar. 19, 2002, the entire contents ofeach of which are hereby incorporated herein by reference.

TECHNICAL FIELD

The present invention generally relates to a recording method andapparatus, a reproducing method and apparatus, recording medium, programand a disc medium, and more particularly to a method of, and apparatusfor, recording address information as wobbles of a groove to a discmedium, a method of, and apparatus for, reproducing address informationrecorded as wobbles of a groove on a disc medium, a recording mediumhaving recorded therein a program for the address information recordingand reproduction, the program, and a disc medium having such a grooveformed thereon.

BACKGROUND ART

Heretofore, a disc medium such as an optical disc, magnetic disc,magneto-optical disc or the like has a spiral groove formed thereon forthe purpose of tracking. It is already known to record addressinformation by wobbling the groove adaptively to the addressinformation.

For example, a CD-R (compact disc—Recordable) and MD (mini-disc) hasformed thereon a spiral groove wobbled adaptively to an FM-modulatedcarrier signal (will be referred to as “FM modulation signal” hereunder)on the basis of address information. With the wobbles of the grooveadaptively to the FM modulation signal, however, address informationcannot be detected with a high accuracy and a given address cannot beaccessed with a high accuracy when recording data to a disc medium andfor reproducing data recorded in a disc medium. Therefore, for recordingdata to a disc medium, a very large link area (where no data is to bewritten) has to be provided before and after the data, which leads to awaste use of the recording area of the disc medium.

DISCLOSURE OF THE INVENTION

Accordingly, the present invention has an object to overcome theabove-mentioned drawbacks of the related art by providing a recordingapparatus and method, reproducing apparatus and method, recordingmedium, program and a disc medium, which make it possible to access agiven address quickly and accurately through accurate reproduction ofaddress information.

The above object can be attained by providing an apparatus for recordingaddress information to a disc medium, the apparatus including accordingto the present invention:

means for generating address information composed of a sync signalincluding a plurality of sync unit patterns, address data and an errorcorrection code for the address data;

means for making MSK modulation of a carrier signal correspondingly tothe address information generated by the address information generatingmeans to generate an MSK modulation signal; and

means for forming, on the disc medium, a spiral groove wobbledadaptively to the MSK modulation signal generated by the modulatingmeans.

In the above recording apparatus, an optical disc may be used as thedisc medium. Also, the modulating means may generate an MSK modulationsignal consisting of a non-modulated part and a modulated part by makingMSK modulation of the carrier signal correspondingly to the addressinformation generated by the address information generating means. Thefrequency of the non-modulated part of the MSK modulation signal may bethe same as that of the carrier signal while the frequency of themodulated part of the MSK modulation may be 1.5 times higher than thatof the carrier signal. Also, correspondingly to 1-bit data “0” of theaddress information, the modulating means may generate an MSK modulationsignal having a non-modulated part and modulated part allocated in afirst order, and correspondingly to 1-bit data “1” of the addressinformation, and an MSK modulation signal of a second pattern having anon-modulated part and modulated part allocated in a second order.

Also, the above object can be attained by providing a method forrecording address information to a disc medium, the method including,according to the present invention:

a generating step of generating address information composed of a syncsignal including a plurality of sync unit patterns, address data and anerror correction code for the address data;

a modulation step of making MSK modulation of a carrier signalcorrespondingly to the address information generated by the addressinformation generating means to generate an MSK modulation signal; and

a forming step of forming, on the disc medium, a spiral groove wobbledadaptively to the MSK modulation signal generated by the modulatingmeans.

Also, the above object can be attained by providing a recording mediumhaving a computer-readable program for recording address information toa disc medium, the program including, according to the presentinvention:

a generating step of generating address information composed of a syncsignal including a plurality of sync unit patterns, address data and anerror correction code for the address data;

a modulation step of making MSK modulation of a carrier signalcorrespondingly to the address information generated by the addressinformation generating means to generate an MSK modulation signal; and

a forming step of forming, on the disc medium, a spiral groove wobbledadaptively to the MSK modulation signal generated by the modulatingmeans.

Also, the above object can be attained by providing a program forcausing a computer, which controls operations for recording addressinformation to a disc medium, to execute, according to the presentinvention:

a generating step of generating address information composed of a syncsignal including a plurality of sync unit patterns, address data and anerror correction code for the address data;

a modulation step of making MSK modulation of a carrier signalcorrespondingly to the address information generated by the addressinformation generating means to generate an MSK modulation signal; and

a forming step of forming, on the disc medium, a spiral groove wobbledadaptively to the MSK modulation signal generated by the modulatingmeans.

Also, the above object can be attained by providing an apparatus forreproducing an address on a disc medium on the basis of wobbles of agroove formed on the disc medium, the apparatus including according tothe present invention:

radiating means for radiating laser light to the disc medium;

return light detecting means for detecting return light from the discmedium to generate a return light signal corresponding to the returnlight thus detected;

wobbling signal generating means for generating a wobbling signalcorresponding to the wobbles of the groove on the basis of the returnlight signal generated by the return light detecting means;

extracting means for extracting an MSK modulation signal by removing anoise component from the wobbling signal generated by the wobblingsignal generating means;

demodulating means for demodulating the MSK modulation signal to recoveraddress information composed of a sync signal including a plurality ofsync unit patterns, address data and an error correction code for theaddress data;

sync unit pattern detecting means for detecting at least one of theplurality of sync unit patterns included in the sync signal in theaddress information recovered by the demodulating means;

acquiring means for acquiring the address data and error correction codefor the address data from the address information on the basis of theposition of the sync unit pattern detected by the sync unit patterndetecting means; and

reproducing means for reproducing the address on the basis of theaddress data and the error correction code for the address data,acquired by the acquiring means.

Note that in this address information reproducing apparatus, an opticaldisc can be used as the disc medium.

Also, the above object can be attained by providing a method forreproducing an address on a disc medium on the basis of wobbles of agroove formed on the disc medium, the method including, according to thepresent invention:

a radiating step of radiating laser light to the disc medium;

a return light detecting step of detecting return light from the discmedium to generate a return light signal corresponding to the returnlight thus detected;

a wobbling signal generating step of generating a wobbling signalcorresponding to the wobbles of the groove on the basis of the returnlight signal generated in the return light detecting step;

an extracting step of extracting an MSK modulation signal by removing anoise component from the wobbling signal generated in the wobblingsignal generating step;

a demodulating step of demodulating the MSK modulation signal to recoveraddress information composed of a sync signal including a plurality ofsync unit patterns, address data and an error correction code for theaddress data;

a sync unit pattern detecting step of detecting at least one of theplurality of sync unit patterns included in the sync signal in theaddress information recovered in the demodulating step;

an acquiring step of acquiring the address data and error correctioncode for the address data from the address information on the basis ofthe position of the sync unit pattern detected in the sync unit patterndetecting step; and

a reproducing step of reproducing the address on the basis of theaddress data and the error correction code for the address data,acquired in the acquiring step.

Also, the above object can be attained by providing a recording mediumhaving recorded therein a computer-readable program including, accordingto the present invention:

a radiating step of radiating laser light to the disc medium;

a return light detecting step of detecting return light from the discmedium to generate a return light signal corresponding to the returnlight thus detected;

a wobbling signal generating step of generating a wobbling signalcorresponding to the wobbles of the groove on the basis of the returnlight signal generated in the return light detecting step;

an extracting step of extracting an MSK modulation signal by removing anoise component from the wobbling signal generated in the wobblingsignal generating step;

a demodulating step of demodulating the MSK modulation signal to recoveraddress information composed of a sync signal including a plurality ofsync unit patterns, address data and an error correction code for theaddress data;

a sync unit pattern detecting step of detecting at least one of theplurality of sync unit patterns included in the sync signal in theaddress information recovered in the demodulating step;

an acquiring step of acquiring the address data and error correctioncode for the address data from the address information on the basis ofthe position of the sync unit pattern detected in the sync unit patterndetecting step; and

a reproducing step of reproducing the address on the basis of theaddress data and the error correction code for the address data,acquired in the acquiring step.

Also, the above object can be attained by providing a program forcausing a computer, which controls operations for reproducing an addresson a disc medium on the basis of wobbles of a groove formed on the discmedium, to execute, according to the present invention:

a radiating step of radiating laser light to the disc medium;

a return light detecting step of detecting return light from the discmedium to generate a return light signal corresponding to the returnlight thus detected;

a wobbling signal generating step of generating a wobbling signalcorresponding to the wobbles of the groove on the basis of the returnlight signal generated in the return light detecting step;

an extracting step of extracting an MSK modulation signal by removing anoise component from the wobbling signal generated in the wobblingsignal generating step;

a demodulating step of demodulating the MSK modulation signal to recoveraddress information composed of a sync signal including a plurality ofsync unit patterns, address data and an error correction code for theaddress data;

a sync unit pattern detecting step of detecting at least one of theplurality of sync unit patterns included in the sync signal in theaddress information recovered in the demodulating step;

an acquiring step of acquiring the address data and error correctioncode for the address data from the address information on the basis ofthe position of the sync unit pattern detected in the sync unit patterndetecting step; and

a reproducing step of reproducing the address on the basis of theaddress data and the error correction code for the address data,acquired in the acquiring step.

The disc medium according to the present invention has formed thereon aspiral groove wobbled adaptively to an MSK modulation signalcorresponding to address information composed of a sync signal includinga plurality of sync unit patterns, address data and an error correctioncode for the address data. It should be noted that an optical disc maybe used as the disc medium.

In the above address information recording apparatus and method andprogram, there are generated address information composed of the syncsignal including the plurality of sync unit patterns, address data andan error correction code for the address data, and a carrier signal isMSK-modulated correspondingly to the address information thus generated,to thereby generate an MSK modulation signal. Further, the groovewobbled adaptively to the MSK modulation signal thus generated is formedon a disc medium.

In the above address information reproducing apparatus and method andprogram, laser light is radiated to a disc medium, return light from thedisc medium is detected, a return light signal is generatedcorresponding to the return light, and a wobbling signal correspondingto the wobbles of the groove is generated on the basis of the returnlight signal thus generated, a noise component is removed from thewobbling signal thus generated and an MSK modulation signal isextracted. Also, the MSK modulation signal thus extracted is demodulatedto recover address information composed of a sync signal including aplurality of sync unit patterns, address data and an error correctioncode for the address data. Further, at least one of the sync unitpatterns included in the sync signal of the address information thusrecovered is detected, the address data and error correction code forthe address data are acquired from the address information on the basisof the position of the sync unit pattern thus detected, and an addressis reproduced based on the address data and error correction code forthe address data, thus acquired.

Also, the above object can be attained by providing a disc medium havingformed thereon according to the present invention, a spiral groovewobbled adaptively to an MSK modulation signal corresponding to addressinformation composed of a sync signal including a plurality of sync unitpatterns, address data and error correction code for the address data.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a block diagram of the address recording apparatus accordingto the present invention.

FIG. 2 is a plan view of an optical disc having a spiral groove formedthereon.

FIG. 3 is a plan view showing how the grooves are wobbled.

FIG. 4 shows an MSK modulation signal composed of a non-modulated partand modulated part.

FIG. 5 shows how the groove is wobbled correspondingly to a monotone bitand ADIP bit.

FIG. 6 shows the configuration of address information (ADIP)corresponding to a write-read cluster RUB.

FIG. 7 shows the configuration of an 8-bit sync part.

FIGS. 8A to 8D show four types of sync unit patterns included in thesync part.

FIG. 9 shows the configuration of a 75-bit data part.

FIGS. 10A and 10B show two different ADIP unit patterns.

FIG. 11 explains an error correction code for address data.

FIG. 12 shows a flow of operations made in recording an address in theaddress recording apparatus.

FIG. 13 is a block diagram of an optical disc drive for reproducingaddress information from an optical disc.

FIGS. 14A to 14H explain together how a DMSK modulation signal isdemodulated by the wobbling circuit.

FIGS. 15A to 15H explain together how a GMSK modulation signal isdemodulated by the wobbling circuit

BEST MODE FOR CARRYING OUT THE INVENTION

The recording apparatus and method, reproducing apparatus and method,recording medium, program and disc medium, according to the presentinvention will be described herebelow with reference to the accompanyingdrawings. The address recording apparatus according to the presentinvention is constructed as shown in FIG. 1. During production of anoptical disc 5, the apparatus forms, on the optical disc 5, a groove Ghaving a spiral form intended for tracking as shown in FIG. 2 andwobbled adaptively to address information as shown in FIG. 3.

As shown, the address recording apparatus according to the presentinvention includes an address generator 1. The address generator 1generates address information indicating the position of address dataand which is composed of a sync signal, address data and an errorcorrection code (ECC) for the address data, pre-encodes and supplies itto a modulator 3. The address recording apparatus includes also acarrier signal generator 2 to generate a carrier signal x(t) (=cos θ(t))which is to carry the address information, and supplies the signal tothe modulator 3.

The modulator 3 is provided to make MSK (minimum shift keying)modulation of a carrier signal (as shown in FIG. 4A) supplied from thecarrier signal generator 2, correspondingly to the pre-encoded addressinformation supplied from the address generator 1, and supplies aresultant MSK modulation signal (as shown in FIGS. 4B to 4D) to awobbling unit 4. It should be noted that the MSK modulation may be DMSK(differential minimum shift keying) modulation or GDMSK (Gausianfiltered difference minimum shift keying) modulation.

Of the MSK modulation signal, a part for one cycle (will be referred toas “one wobble” hereunder), having the same frequency as that of thecarrier signal as shown in FIG. 4B, corresponds to a code “0” of thepre-encoded address information. Also, of the MSK modulation signal, apart for 1.5 cycles (equal to one wobble of the carrier signal), havinga frequency 1.5 times higher than that of the carrier signal,corresponds to a code “1” of the address information, as shown in FIG.4C. Therefore, the MSK modulation signal as shown in FIG. 4D for examplecorresponds to a code “1010” of the pre-encoded address information.

Of the MSK modulation signal, a part having the same frequency as thatof the carrier signal will be referred to as “non-modulated part”hereunder. Also, of the MSK modulation signal, a part having a frequency1.5 times higher than that of the carrier signal will be referred to as“modulated part” hereunder. It should also be noted that the frequencyof a modulated part will be described using a number of wobbles of acorresponding non-modulated part.

The wobbling unit 4 forms, on the optical disc 5, a spiral groovewobbled according to an MSK modulation signal supplied from themodulator 3.

Note that as shown in FIG. 5, address information of 1 bit is classifiedinto a monotone bit including a first signal for 42 wobbles, and an ADIP(address in pre-groove) bit or the like including a second signal for 42wobbles.

The address recording apparatus further includes a controller 6 tocontrol a drive 7 to read a control program from a magnetic disc 8,optical disc 9, magneto-optical disc 10 or a semiconductor memory 11,and then control the entire address recording apparatus on the basis ofthe control program thus read.

FIG. 6 shows the configuration of address information recordedcorrespondingly to a write-read cluster RUB (recording unit block) ofthe optical disc 5. Two pieces of address information (ADIP) arerecorded in the read-write cluster RUB. Each piece of addressinformation is of 83 bits of which 8 bits are for a sync part (SYNC)indicating a sync signal, and 75 bits are for a data part indicatingaddress data and ECC for the address data.

FIG. 7 shows the configuration of a sync part of 8 bits. As shown, thesync part is composed of four sync blocks “1” to “4” each including amonotone bit and a sync bit.

As shown in FIGS. 8A to 8D, a sync bit (for 42 wobbles) is composed of async unit for 14 wobbles including the second signal and a monotone for28 wobbles (first signal).

FIGS. 8A to 8D show wobbles for sync blocks “1” to “4”, namely, an MSKmodulation signal.

The sync unit in the sync block “1” is formed as wobbles indicating afirst sync unit pattern “10101010000000” as shown in FIG. 8A. The syncunit in the sync block “2” is formed as wobbles indicating a second syncunit pattern “10100010100000” as shown in FIG. 8B. The sync unit in thesync block “3” is formed as wobbles indicating a third sync unit pattern“10100000101000” as shown in FIG. 8C. The sync unit in the sync block“4” is formed as wobbles indicating a fourth sync unit pattern“10100000001010” as shown in FIG. 8D.

The sync part of 8 bits will include all the above-mentioned first tofourth sync unit patterns. For reproducing address information, when atleast one of the first to fourth sync unit patterns can be reproduced,the position of the sync part, that is, the address information, canaccurately be determined.

FIG. 9 shows the configuration of the 75-bit data part. As will be seenfrom FIG. 9, the data part includes fifteen ADIP blocks “1” to “15” eachcomposed of a monotone bit and four ADIP bits.

As shown in FIG. 10A, one monotone bit forming a part of each ADIP blockconsists of a non-modulated part for 42 wobbles. FIG. 10B shows that oneof the four ADIP bits forming each ADIP block consists of an ADIP unitfor 6 wobbles including a modulated part, and a non-modulated part for36 wobbles.

The ADIP unit for 6 wobbles including the modulated part includes firstand second ADIP unit patterns.

The ADIP unit in the ADIP bit, equivalent to 1-bit digital data “1” inthe address data in the address information, consists of the first ADIPunit pattern “101000”. Also, the ADIP unit in the ADIP bit, equivalentto 1-bit digital data “0” in the address data in the address informationconsists of the second ADIP unit pattern “001010”.

FIG. 11 shows address data and an ECC for the address data. As shown, anECC (parity) of 32 bits (=8 nibbles) is added to address data of 28 bits(=7 nibbles). It should be noted that the 28-bit address data includes a20-bit RUB number, 2-bit RUB address number, 2-bit information for amultilayer disc and a four reserved bits. The error correction method isthe nibble-based Reed-Solomon Coding RS (15, 7, 9).

Referring now to FIG. 12, there is illustrates in the form of a flowchart operations made for recording of address information in theaddress recording apparatus according to the present invention. Theaddress recording will be described below with reference to FIG. 12.

In step S1 shown in FIG. 12, the address generator 1 generates addressinformation which is to be recorded to the optical disc 5 and composedof a sync signal, address data and an ECC for the address data,pre-encodes the address information and supplies it to the modulator 3.At the same time, the carrier signal generator 2 generates a carriersignal which is to carry the address information, and supplies thesignal to the modulator 3.

In step S2, the modulator 3 makes MSK modulation of the carrier signalsupplied from the carrier signal generator 2 on the basis of thepre-encoded address information supplied from the address generator 1,and supplies a resultant MSK modulation signal to the wobbling unit 4.

Next in step S3, the wobbling unit 4 forms, on the optical disc 5, aspiral groove wobbled adaptively to the MSK modulation signal suppliedfrom the modulator 3.

With the above address recording operations made by the addressrecording apparatus, address information can be generated by including,in a sync signal, four different sync unit patterns any one of whichmakes it possible to locate the sync signal when it can be detected andthere can be formed on the optical disc 5 a groove wobbled adaptively toan MSK modulation signal corresponding to the address information thusgenerated.

Thus it is possible to provide an optical disc 5 in which an address canbe accessed with an extremely high accuracy. Therefore, since no uselessarea such as link area has to be provided in a data recording area, anoptical disc 5 can be provided of which the data recording area can beused effectively.

Referring now to FIG. 13, there is schematically illustrated in the formof a block diagram a concrete example of the construction of an opticaldisc drive which writes and reads arbitrary data to and from the opticaldisc 5 having address information written as wobbles of a groove thereonby the address recording apparatus according to the present invention.

As shown in FIG. 13, the optical disc drive includes a control circuit21 which controls components of the optical disc drive according to acontrol program recorded in a recording medium 22. More specifically,the control circuit 21 controls the components of the optical disc driveaccording to a write command supplied from an external AV apparatus orthe like (not shown) via an AV interface 23 to write, to the opticaldisc 5, a mark corresponding to recording data supplied from the AVapparatus. Also, the control circuit 21 controls the optical disc drivecomponents to read a mark recorded in the optical disc 5 according to aread command supplied from the AV apparatus via the AV interface 23,reproduce the recorded data, and supply it to the AV apparatus via theAV interface 23.

The optical disc drive includes also a spindle circuit 24 to control therotation of a spindle motor 26 according to a command from the controlcircuit 21, and a servo circuit 25 to cause an optical pickup 27 to seekan address specified by the control circuit 21 and control the focusservo and tracking servo of the optical pickup 27 according to a focuserror signal and tracking error signal supplied from an optical headcircuit 28. The spindle motor 26 rotates the optical disc 5 under thecontrol of the spindle circuit 24.

The optical pickup 27 consists of a laser output system, return linedetecting system, biaxial actuator, etc. For data recording, the opticalpickup 27 is controlled by the optical head circuit 28 to radiate laserlight to the optical disc 5, thereby forming a mark on the optical disc5. For data reproduction, the optical pickup 27 radiate laser light ontothe optical disc 5, detects return light from the optical disc 5 andgenerate a corresponding return light signal, and supplies it to theoptical head circuit 28.

For data recording, the optical head circuit 28 controls the laseroutput from the optical pickup 27 correspondingly to a header signal orwrite-compensated signal supplied from the write-read circuit 29. Fordata reproduction, the optical head circuit 28 generates an RF signalcorresponding to an embossed pit and mark recorded on the optical disc 5on the basis of the return light signal from the optical pickup 27, andsupplies the RF signal to the write-read circuit 29. Further, for datareproduction, the optical head circuit 28 generates a focus error signaland tracking error signal on the basis of the return light signal fromthe optical pickup 27, and supplies it to the servo circuit 25 whichwill then generate a pushpull (will be referred to as “pp” hereunder)signal. The pp signal is supplied to a wobbling circuit 32.

For data recording, the write-read circuit 29 is controlled by thecontrol circuit 21 to make write compensation of a signal supplied froma modem circuit 30 and supply the compensated signal to the optical headcircuit 28. For data reproduction, the write-read circuit 29 convertsthe RF signal from the optical head circuit 28 into binarized data andsupplies the data to the modem circuit 30.

For data recording, the modem circuit 30 is controlled by the controlcircuit 21 to modulate ECC-added recording data supplied from an errorcorrection circuit 31 and supply the resultant signal to the write-readcircuit 29. For data reproduction, the modem circuit 30 demodulates thebinarized data supplied from the write-read circuit 29 and supplies theresultant read data to the error correction circuit 31.

For data recording, the error correction circuit 31 is controlled by thecontrol circuit 21 to add an error correction code (ECC) to therecording data supplied from the external AV apparatus or the like viathe AV interface 23, and supplies the data to the modem circuit 30. Fordata reproduction, the error correction circuit 31 corrects any error ofread data supplied from the modem circuit 30 on the basis of the ECC,and supplies the corrected data to the external AV apparatus or the likevia the AV interface 23.

The wobbling circuit 32 generates and demodulates a wobbling signal(equal to the MSK modulation signal including a noise component)corresponding to wobbles of a groove on the basis of the pp signalsupplied from the optical head circuit 28, and supplies the recoveredaddress information (including a sync signal, address data and errorcorrection code for the address data) to a address decoder/timinggenerator (DEC/TG) 33.

The DEC/TG 33 detects the position of a sync part by detecting at leastone of the four different sync unit patterns included in the sync partfrom the address information supplied from the wobbling circuit 32,generates an address based on address data and ECC for the address dataincluded in a data part next to the sync unit, and supplies the addressto the control circuit 21. Also, the DEC/TG 33 generates a timing signalon the basis of the detected sync part, and supplies the timing signalto various circuits in the optical disc drive via the control circuit21.

Next, how the wobbling circuit 32 recovers address information bydemodulating a wobbling signal will be described with reference to FIGS.14 and 15.

First, use of the DMSK modulation for the MSK modulation will bedescribed herebelow. Address information as original data shown in FIG.14A is made a signal “Mod data” as shown in FIG. 14B by a differentialencoding as the pre-encoding, it is then subjected to MSK modulation andrecorded as an MSK modulation (DMSK modulation) signal as shown in FIG.14C on the optical disc 5.

The wobbling circuit 32 generates a wobbling signal (DMSK modulationsignal including a noise component) from the pp signal, and extracts acarrier signal as shown in FIG. 14D from the wobbling signal. Then, thewobbling circuit 32 generates a signal “Demod out” as shown in FIG. 14Eby multiplying the wobbling signal by the carrier signal, removes thenoise component from the signal by means of an incorporated lowpassfilter or the like to generate a signal “LPF out” as shown in FIG. 14F.

Note that the factor of the lowpass filter (e.g., 27-tap FIR filter)incorporated in the wobbling circuit 32 is as follows by way of example.The sampling frequency is eight times higher then the wobblingfrequency.

−0.000640711

−0.000865006

0.001989255

0.009348803

0.020221675

0.03125

0.040826474

0.050034929

0.05852149

0.065960023

0.072064669

0.076600831

0.079394185

0.080337385 (center)

0.079394185

0.076600831

0.072064669

0.065960023

0.05852149

0.050034929

0.040826474

0.03125

0.020221675

0.009348803

0.001989255

−0.000865006

−0.000640711

Further, the wobbling circuit 32 binarizes the signal “LPF out” toprovide a signal “Demod data” as shown in FIG. 14G. This signal issubjected to NRZ conversion to recover a signal (pre-encoded addressinformation) as shown in FIG. 14H.

Next, use of the GDMSK modulation for the MSK modulation will bedescribed. Address information as original data shown in FIG. 14A ismade a signal as shown in FIG. 15A by a differential encoding as thepre-encoding, the resultant signal is passed through a Gausian filter toprovide a signal “Mod data” as shown in FIG. 15B, and then the signal“Mod data” is subjected to DMSK modulation and recorded as an MSKmodulation (GDMSK modulation) signal as shown in FIG. 15C on the opticaldisc 5.

The wobbling circuit 32 generates a wobbling signal (GDMSK modulationsignal including a noise component) from the pp signal, and extracts acarrier signal as shown in FIG. 15D from the wobbling signal thusgenerated. Then, the wobbling circuit 32 generates a signal “Demod out”as shown in FIG. 14E by multiplying the wobbling signal by the carriersignal, removes the noise component from the signal by means of anincorporated lowpass filter or the like to generate a signal “LPF out”as shown in FIG. 14F.

Further, the wobbling circuit 32 binarizes the signal “LPF out” toprovide a signal “Demod data” as shown in FIG. 15G. This signal issubjected to NRZ conversion to recover a signal (pre-encoded addressinformation) as shown in FIG. 15H.

As having been described in the foregoing, the optical disc drive candetect the position of a sync part by detecting at least one of the fourtypes of sync unit patterns included in the sync part. Thus, it ispossible to acquire address data and ECC for the address data includedin a data part next to the sync part and generate an address from theaddress data and ECC. So, it is possible to improve the address errorrate for reproduction of data and accurately access a given address onthe optical disc 5.

Also, according to the present invention, since the second signal of theMSK modulation signal has a frequency 1.5 times higher than that of thefirst signal (carrier signal), the range of a frequency to be detectedin the wobbling circuit 32 is very narrow. Thus, the bandwidth of afrequency to be reproduced can be narrowed. Further, the S/N(signal-to-noise) ratio can be improved for the error rate of an addressto be lower.

Note that the present invention may be applied for recording andreproducing address information to and from the optical disc 5 as wellas from disc-shaped recording media of all types.

The aforementioned series of operations can be carried out by ahardware, and also by a software. In the latter case, a program formingthe software is installed from a recording medium in a computer havingdedicated hardware for execution of the program or in a general-purposepersonal computer, for example, which can execute various functions byinstalling a variety of programs.

As shown in FIG. 1, the recording medium is not only a package mediumsuch as a magnetic disc 8 (including a floppy disc), optical disc 9(CD-ROM (=compact disc—read-only memory), DVD (digital versatile disc),magneto-optical disc 10 (including mini disc (MD)) or a semiconductormemory 11, distributed to the users for serving the program and havingthe program recorded therein, but a ROM or hard disc built in a computerin advance and having the program recorded therein.

Note that in the present invention, the steps of describing the programto be recorded in a recording medium include, of course, operations madetime-serially in the described order of them, and also operations madenot time-serially but in parallel or individually.

INDUSTRIAL APPLICABILITY

As having been described in the foregoing, the address informationrecording apparatus and method and the first program according to thepresent invention are such that an MSK modulation signal is generated bymaking MSK modulation of a carrier signal correspondingly to addressinformation composed of a sync signal including a plurality of sync unitpatterns, address data and an error correction code of the address dataand there is formed a spiral groove wobbled adaptively to the MSKmodulation signal thus generated. Thus, it is possible to record, to thedisc medium, address information which permits accurate detection of theposition of the sync signal.

Also, the address information reproducing apparatus and method and thesecond program according to the present invention are such that an MSKmodulation signal is extracted by removing a noise component from agenerated wobbling signal and the MSK modulation signal thus extractedis demodulated to recover address information composed of a sync signalincluding a plurality of sync unit patterns, address data and an errorcorrection code of the address data. Thus, it is possible to access agiven address quickly and accurately.

Since the disc medium according to the present invention has formedthereon a spiral groove wobbled adaptively to an MSK modulation signalcorrespondingly to address information composed of a sync signalincluding a plurality of sync unit patterns, address data and an errorcorrection code of the address data, it is possible to access a givenaddress quickly and accurately.

1. An apparatus for manufacturing a disc comprising: means forgenerating address information indicating a position of address datacomposed of a sync signal including a plurality of sync unit patterns,address data, and error correction code for the address data, and meansfor forming, on the disc, a spiral groove wobbled based on an MSKmodulation signal produced by MSK modulation of a carrier signalcorresponding to the address information, the spiral groove includingthe sync signal including the plurality of sync unit patterns, theaddress data, and the error correction code for the address data,wherein said MSK modulation signal includes at least one non-modulatedpart and at least one modulated part, and wherein said at least onenon-modulated part and at least one modulated part are allocated in afirst order, corresponding to 1-bit data “0” of the address information,and said at least one non-modulated part and at least one modulated partare allocated in a second order, corresponding to 1 bit data “1” of theaddress information.
 2. The apparatus as set forth in claim 1, whereinthe disc is an optical disc.
 3. An apparatus for manufacturing a disccomprising: a controller configured to control forming, on the disc, aspiral groove wobbled based on an MSK modulation signal produced by MSKmodulation of a carrier signal corresponding to address information, thespiral groove including a sync signal including a plurality of sync unitpatterns, address data, and error correction code for the address data,wherein said MSK modulation signal includes at least one non-modulatedpart and at least one modulated part, and wherein said at least onenon-modulated part and at least one modulated part are allocated in afirst order, corresponding to 1-bit data “0” of the address information,and said at least one non-modulated part and at least one modulated partare allocated in a second order, corresponding to 1 bit data “1” of theaddress information.
 4. The apparatus as set forth in claim 3, whereinthe disc is an optical disc.
 5. An apparatus for recording data on adisc according to address data detected based on wobbles of one or moregroove formed on a disc comprising: means for obtaining address data byerror correcting address information read from the disc; wherein saidaddress information is represented by an MSK modulation signal includingat least one non-modulated part and at least one modulated part; andwherein said at least one non-modulated part and at least one modulatedpart are allocated in a first order, corresponding to 1-bit data “0” ofthe address data, and said at least one non-modulated part and at leastone modulated part are allocated in a second order, corresponding to 1bit data “1” of the address data; and means for recording arbitrary datareferring to the obtained address data from the disc.
 6. The apparatusas set forth in claim 5, wherein the disc is an optical disc.
 7. Anapparatus for recording data on a disc according to address datadetected based on wobbles of one or more groove formed on a disccomprising: a controller configured to control recording arbitrary datareferring to address data on the disc; and wherein said address data isobtained by error correcting address information; wherein said addressinformation is represented by an MSK modulation signal including atleast one non-modulated part and at least one modulated part; andwherein said at least one non-modulated part and at least one modulatedpart are allocated in a first order, corresponding to 1-bit data “0” ofthe address data, and said at least one non-modulated part and at leastone modulated part are allocated in a second order, corresponding to 1bit data “1” of the address data.
 8. The apparatus as set forth in claim7, wherein the disc is an optical disc.
 9. A disc comprising: at leastone spiral groove wobbled adaptively to an MSK modulation signalcorresponding to address information obtained by calculating addressdata to add error correction code, and by adding a sync signal includinga plurality of sync unit patterns wherein said MSK modulation signalincludes at least one non-modulated part and at least one modulatedpart; said at least one non-modulated part and at least one modulatedpart are allocated in a first order corresponding to 1-bit data “0” ofthe address data, and said at least one non-modulated part and at leastone modulated part are allocated in a second order, corresponding to 1bit data “1” of the address data.
 10. The disc as set forth in claim 9,wherein the disc is an optical disc.
 11. A method for manufacturing adisc comprising: forming, on the disc, a spiral groove wobbled based onan MSK modulation signal produced by MSK modulation of a carrier signalcorresponding to address information, the spiral groove including a syncsignal including a plurality of sync unit patterns, address data, anderror correction code for the address data, wherein said MSK modulationsignal includes at least one non-modulated part and at least onemodulated part, and wherein said at least one non-modulated part and atleast one modulated part are allocated in a first order, correspondingto 1-bit data “0” of the address information, and said at least onenon-modulated part and at least one modulated part are allocated in asecond order, corresponding to 1 bit data “1” of the addressinformation.
 12. The method as set forth in claim 11, wherein the discis an optical disc.